The identification and targeting of dysregulated signal transduction pathways underlying oncogenic states has heralded a new and exciting approach to cancer therapy. The overall objective of our work is to determine whether simultaneous targeting of multiple oncogenic signaling pathways in cancer is safe and effective in humans. We will use chronic myelogenous leukemia (CML) as a disease model, and employ a combination of highly-specific, small molecular inhibitors directed against the Bcr-Abl and mammalian target of rapamycin (mTOR) kinases. The rationale for this approach is based on our recent work demonstrating that combined treatment with imatinib and the mTOR inhibitor, rapamycin, acts synergistically against CML progenitors, as well as overcomes various forms of imatinib resistance. The objectives of this proposal are: 1. To conduct a phase I study using the combination of the rapamycin analog, CCI-779, and imatinib mesylate in patients with high-risk CML; and 2. To validate laboratory correlates for target evaluation and response prediction. These objectives will be accomplished using an adaptive phase I design, employing a fixed dose of imatinib in combination with a dose-escalation schedule for CCI-779 in patients with high-risk CML. An integral part of this study will be the validation of translational correlates, including target identification, evaluation of biomarkers for effective targeting, and response prediction. The specific laboratory correlative studies included in this trial are derived from preliminary data using patient samples in the Principle Investigator's laboratory. This study has been approved and is sponsored by the Cancer Therapy Evaluation Program of the National Cancer Institute, and will enroll patients from the Irvine, San Diego, and Davis Campuses of the University of California. The clinical data and laboratory studies outlined in our proposal will form the basis for a future phase II trial in patients with high-risk CML. Since deregulated kinase activity is known to contribute to a wide range of malignancies, these studies will have applicability to cancer therapy in general. [unreadable] [unreadable]